A multilevel modular dc-dc converter topology

Abstract

A multilevel modular DC-DC power conversion topology based on cascaded H-Bridge converters in a double П configuration is presented. The topology is intended to interconnect large power DC networks. A two level control hierarchy is used to regulate the DC voltage of each H-bridge module. At the top level, DC and circulating AC currents are used to control the total energy converter in all branches (both parallels and series) of each П arrange. At bottom level, the voltage balance of a converter branch, which comprises N H-bridge modules, is carried out by balancing (N-1) capacitor voltage deviations, with respect to the average capacitor voltage. The entire topology and control strategies are simulated in a PSIM environment. Simulation results with three H-bridge converters per branch are shown and preliminary experimental results with a low power prototype are also included.